The invention relates to a device for deformation of the end area of a glass tube for forming a mouth area of a vial and to a process for forming a vial and the use of the device in a vial machine.
Many devices for the production of hollow articles such as vials, ampules, etc, from glass tube are known. Since these articles are mass-produced, low-cost and fast production is necessary.
DE-PS 12 61 638 describes a known device of this type, in which a ring of receiving devices rotates workpieces in the form of glass tubes in a workpiece path past at least one processing station. The processing station contains swiveling arms which carry forming parts. The forming parts are swung into the workpiece path and can form the workpieces on a section of the workpiece path. The section is substantially greatly limited by the size and arrangement of the arms. To have the time available necessary for a forming process, the ring with the workpieces has to be stopped during the forming or is allowed to turn only very slowly. The forming process can be divided into several individual forming processes, as a result of which many processing stations for processing the same point on the vial become necessary. With this device the arm has to be swung back quickly to the starting position after forming to have more time available for forming. This leads to increased mechanical stress and correspondingly to increased wear.
To enlarge the section on which the forming takes place, in a device known from DE-PS 15 96 410 the forming rollers have been placed on a conveyor device, which for the period of forming moves at the angular speed of the ring along with the workpieces and parallel to the workpieces. In this arrangement, either the workpiece to be formed or the conveyor device is stationary. To form the next workpiece during the return of the conveyor device, several conveyor devices with forming rollers have to be used, and the conveyor devices can be connected to one another, e.g., by a chain, so that, while the first conveyor device returns, another conveyor device for forming moves beside the next workpiece. In this way, each conveyor device has a processing pause of at least 100% of the forming time of a vial. By tolerances of the individual conveyor devices and of the forming rollers vial types differing somewhat from one another result corresponding to the number of conveyor devices in this device.